PilotOutlook API

From their site: This API provides geo-coordinates, city, state, epoch, runway and other information for about 40,000 airports. It is the largest database of airports available online. Add data about airports to your application utilizing the AirportInfo library. Get IATA Code, Landing Facility Type - Airport, Heliport etc, Latitude, Longitude, Elevation in Foot MSL, Magnetic Variation and Direction, and PilotOutlook URL for more information.